Figure 5From: Intra-articular injection of collagenase in the knee of rats as an alternative model to study nociception associated with osteoarthritisSynovial membrane histopathology. Images representative of the synovial membrane inflammation one week (A-C) and six weeks (D-F) after injection of saline ( A , D ), 250 U (B, E) or 500 U of collagenase ( C , F ). An increased number of synovial lining cell layers, proliferation of subsynovial tissue and infiltration of inflammatory cells are observed. Changes were most pronounced with the 500 U dose, one week after injection, receding thereafter. Bar: 50 μm.Back to article page